Case 1

24-year-old male presents via EMS after being involved in altercation. According to bystanders, patient was noted to sustain several gunshot wounds from close range, notably to the left anterior chest and left upper extremity. On EMS arrival, patient was diaphoretic but awake, with GCS of 15, heart rate 140 bpm, blood pressure 95/60 mmHg, respiratory rate 26 with room air oxygen saturation of 90%. On arrival in the ED, patient becomes initially combative, then develops altered mental status. Examination now reveals no palpable pulses or measurable blood pressure.

Case 2

3-year-old female presents via EMS after being involved in a roll-over MVA. Patient was apparently not restrained and was thrown 25 feet from the vehicle. EMS noted GCS of 5 on arrival, with abnormal flexion, no eye opening and no verbal response. Cervical collar and back board precautions are in place, as well as splinting of left upper and right lower extremity angulated, open fractures. 20-minutes prior to arrival in the ED, EMS noted loss of palpable pulses and initiated CPR. Patient arrives in ED with staff continuing compressions. Pupillary exam reveals no reactivity with GCS 3.

Introduction:

Traumatic injury is a significant source of morbidity and mortality for all of humankind, and is still the leading cause of death for those ages 1-44 years in industrialized nations.1 Historically, cardiopulmonary arrest linked to acute traumatic injury has had incredibly poor survival rates, which resulted in resuscitative efforts in the setting of Traumatic Cardiac Arrest (TCA) being deemed futile by many. Recent re-examination of TCA, however, has shown that rates of morbidity and mortality approach that of all-cause cardiac arrest.2 Depending on populations examined, survival rates have been documented from 0-17%3, though Leis et al demonstrated a survival rate of 49.9% with complete neurologic recovery seen in 6.6% of all TCA in one study.4 TCA, unlike medical causes of cardiac arrest, typically stem from a brief list of causes: severe head trauma, hypovolemia, tension pneumothorax, pericardial tamponade, and upper airway obstruction. 2,5 Given the reversible nature of several potential causes of TCA, intervention by emergency medical providers in a standard, protocol driven fashion could potentially result in continued improvement of survival among this patient population.

In the case of TCA, presenting rhythm is most commonly that of pulseless electrical activity(PEA), followed by asystole/electromechanical dissociation and ventricular dysrhythmias.6,7 Theories as to why PEA tends to be the initial cardiac rhythm for TCA focus on the low flow circulatory state as cardiac output falls in the setting of tension physiology, pericardial tamponade, progressive hypoxia or hypovolemia.8,9 As such, efforts to resuscitate TCA should be aimed at rapid identification and reversal of the underlying cause.

Management of TCA:

Care for victims of TCA must be initiated at first identification of extremis, as mortality significantly increases as post-arrest time moves beyond 10 minutes. The best outcomes in TCA occur when the victim is identified in the peri-arrest phase and action is taken either to prevent arrest or rapidly reverse it.2 However, the environment and situation surrounding such events is chaotic and disorganized, making such rapid determination and appropriate action difficult. Several algorithms have been published that address the approach the patient, as well as when to deem efforts of resuscitation futile meriting discontinuation.10-13,1 A bundled, protocol driven approach will make resuscitative efforts more reliably initiated or terminated14, but are heavily dependent on the pre-hospital and hospital resources available. Thus, a single algorithm is not likely to be easily fit to all clinical environments.

Hypoxemia

Hypoxemia in the acutely injured patient has several potential causes, including airway obstruction (partial vs complete), asphyxia, and respiratory failure due to lack of ventilatory drive (cervical spinal cord injury).11 Efforts to correct the hypoxia and potential ventilatory failure should center on placement of a definitive airway, with knowledge that the most experienced provider be charged with this task. Endotracheal intubation with in-line stabilization of the cervical spine is most ideal, though often unavailable in the prehospital setting. Thus, supraglottic devices or ventilation via bag-valve-mask application may be required. Nasal airways are discouraged, given case reports of intracranial complications in the setting of basilar skull fractures15; however, complications due to inadequate oxygenation and ventilation are far more common in TCA.16 Review of TCA cases that have undergone endotracheal intubation without induction/paralytic medications illustrate higher mortality than in those cases that have required medication-facilitated intubation, likely illustrating a greater level of associated traumatic brain injury.17

Hypovolemia

Critical hypovolemia secondary to hemorrhage, either internal or external, is often cited as the most common cause of preload dependent arrest in trauma.8 Correction of this process must be approached in a two-pronged manner. First, direct compression of potential sources of hemorrhage should be initiated to prevent further losses. This can be done by application of bandages, pressure dressings, hemostatic agents and tourniquets, as well as splinting of fractures. These attempts should be coupled with aggressive resuscitation of volume, preferentially packed red blood cells (PRBCs) as the initial fluid rather than crystalloid.18,19 A ratio of 1:1:1 of PRBCs to fresh frozen plasma (FFP) and platelets has recently been adopted as the best approximation of warm fresh whole blood in acute resuscitation, which would be the ideal resuscitation fluid.18 If unavailable, crystalloid fluid may be used initially, but large volume crystalloid resuscitation should not be employed given the increased complications and mortality.19,20 Volumes transfused should be aimed at restoration of circulating volume, often necessitating “massive transfusion” protocols.8,11

Tension Pneumothorax

Tension physiology in the setting of pneumothorax causes devastating preload elimination and is a common trigger of TCA, necessitating its rapid identification and reversal. Though several methods for decompression are described, direct thoracostomy should be the method employed in TCA. Needle decompression has been described and is still taught as part of ATLS; however, this method is often unsuccessful and has frequent complications.21 Recent studies have demonstrated that standard techniques and equipment are inadequate for decompression of tension physiology.22 Given the timely need for reversal, efforts should be directed instead at performance of finger thoracostomy, a procedure used in the initial stages of tube thoracostomy placement.23 Identification of pneumothorax is often done via X-ray and point-of-care ultrasound in the emergency department, but in the case of TCA this is often not possible. Positive pressure ventilation (PPV), anterior thoracic trauma and need for quick intervention may obscure or prevent such diagnosis. Thus, many algorithms recommend immediate bilateral decompression in blunt, and ipsilateral decompression in penetrating TCA.12,21 Though eventual placement of chest tubes is indicated in the setting of return of spontaneous circulation (ROSC), this can be deferred until successful resuscitation, as PPV can facilitate rapid re-inflation of underlying lung and resolution of tension physiology.24

Pericardial Effusion and Cardiac Tamponade

Traumatic pericardial effusion leading to tamponade physiology is most often seen in penetrating trauma, though may also be present in blunt traumatic events. In the setting of TCA, rapid identification of this pathology has been greatly improved by more widespread use of point-of-care ultrasound.25,26 Significant variations in care of blunt vs penetrating cardiac arrest has existed in the past, though recent studies have suggested that such variation is unwarranted.27 The emergency department thoracotomy (EDT), adapted to the pre-hospital setting in certain arenas, aims at rapid reversal of tamponade, though other sources of TCA may be addressed in the right hands.9 In the setting of penetrating TCA, one study illustrated survival rates after emergency department thoracotomy of nearly 8% with associated good neurologic outcomes.28 Several studies have replicated this success when thoracotomy is performed within the first 10-minutes following TCA, with greatest success when performed after loss of pulses in the emergency department setting.11,29-31Blunt traumatic arrest does not share the same success rates, which is likely associated with the elevated traumatic injury load associated with blunt trauma.27 Despite the lower survival rates, several protocols and professional societies endorse the use of EDT, with several caveats including concern for “obvious head injury incompatible with good outcome.”12,30-31 Unlike that of penetrating TCA, the survival with good neurologic outcome is only 1.5%, with best outcomes in those without suspected head injury, had presence of vital signs on arrival in the ED and underwent <15 minutes of CPR.27

The Role of Point-of-care Ultrasound

Introduction of ultrasound into the trauma evaluation has advanced management considerably. In the setting of TCA, bedside use of the focused assessment with sonography for trauma (FAST) exam allows for rapid determination of the presence of two potentially reversible causes of PEA arrest: pericardial effusion with cardiac tamponade and hypovolemia due to massive hemoperitoneum.9,25-26 Despite its utility, ultrasound may delay certain interventions in TCA resuscitation, such as performance of decompressive thoracostomy, and should not be used outside of the aforementioned indications.

The Role of Cardiopulmonary Resuscitation (CPR)

Initial investigations into the use of CPR showed little utility of these measures in settings of hypovolemia and may actually worsen coronary perfusion.8,32 Additionally, standard advanced cardiac life support (ACLS) measures limit provider access to the chest and hinder potentially life-saving procedures in the setting of TCA.9 As a result, many protocols have eliminated CPR after arrival of the patient in the emergency department. In the pre-hospital setting, however, efforts to maintain perfusion are limited and CPR may be initiated. If efforts with CPR require initiation when the patient remains at great distance from the interventions that may correct the reversible causes, then resuscitative efforts may be futile and discontinuation may be considered. Electrocardiographic evaluation may help providers in triage of potential TCA. Though identification of PEA or asystole predominate, the rare case of ventricular dysrhythmia secondary to commotio cordis may be detected and potentially reversed with defibrillation.8 Finally, medical arrests may be masked by trauma, so great care should be made in evaluating the circumstances of traumatic injury (ie single car motor vehicle accident, fall from height) as ACLS interventions may be indicated. Otherwise, efforts should be focused on the potential correction of the reversible causes of TCA.

The Role of Vasopressors

Smith, et al put this simply: “There is no evidence to support the use of intravenous adrenaline in patients with traumatic cardiac arrest.” Though neurogenic shock as the source of severe hypotension appears to be an exception, blunt trauma induced hypotension treated early with vasopressors has been linked to increased mortality.8,33 Though further study is being done on the use of vasopressin in these settings, current recommendations are to not use these agents in attempted resuscitation of the patient in TCA.

Current Recommendations on When to Terminate/Withhold

Though several studies have contested the components of the 2012 National Association of EMS Physicians and the American College of Surgeons Committee on Trauma recommendations as to withholding or discontinuing resuscitative efforts, they presently serve as a standard of practice that can be used for development of standard operating procedure for pre-hospital and in-hospital providers alike. As such, they are included here:34

The Problem Child: Pediatrics

Despite efforts to develop similar standard operating procedures in the realm of TCA in pediatric populations, efforts have been generally unsuccessful. This is arguably due to a several factors: general reluctance of medical providers to discontinue futile efforts in pediatric patients, proven increased rates of ROSC and survival in pediatric patients, and lack of professional organization guidance or developed protocols.35 The most recent joint statement by several professional organizations offers some guidance, mainly placing grounds for discontinuation on obviously unsurvivable injuries (decapitation, hemicorporectomy, rigor mortis) and prolonged out-of-hospital post-arrest resuscitative efforts.36 Further work in the realm of pediatric cardiac arrest, all-cause and traumatic, is required before more specific recommendations are likely.

References / Further Reading

Hopson LR, Hirsh E, Delgado J, Domeier RM, McSwain NE, Krohmer J. Guidelines for withholding or termination of resuscitation in prehospital traumatic cardiopulmonary arrest: joint position statement of the National Association of EMS Physicians and the American College of Surgeons Committee on Trauma. J Am Coll Surg 2003; 196:106-12.

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